Syria used chlorine bombs systematically in Aleppo, report says

In this undated photo made available Saturday, March 14, 2015, by the Kurdistan Region Security Council (KRSC), a piece of debris that the Kurdistan Region Security Council said is a gas canister lies at the site of a bomb attack on a road between Mosul, Iraq, and the Syrian border in northern Iraq. Kurdish authorities in Iraq said Saturday they have evidence that the Islamic State group used chlorine gas as a chemical weapon against peshmerga fighters, the latest alleged atrocity carried out by the extremist organization now under attack in Tikrit. (AP Photo/Kurdistan Region Security Council)

Photo: Unknown, HOPD / Associated Press

Syrian military helicopters systematically dumped canisters of chlorine gas, a banned weapon, on residential areas of Aleppo at least eight times late last year in the final weeks of the battle to retake the city from rebels, Human Rights Watch said in a detailed study released Monday.

The assertions in the study, if confirmed, would represent one of the most egregious uses of such outlawed weaponry in the war. It would amount to a new level of impunity by the Syrian president, Bashar Assad, who promised to never use chemical arms under an international treaty the government signed more than three years ago.

A U.N. panel that has been investigating reports of chlorine bombs and other chemical weapons in the Syrian war concluded last year that government forces had used them at least three times in 2014 and 2015. The panel is scheduled to provide an update this month.

Assad and his subordinates have repeatedly denied that their side has ever used chemical weapons, calling the evidence fabricated or inconclusive.

But the Human Rights Watch report suggested that Syrian officials had not only disregarded the U.N. findings but also had decided to use chlorine bombs far more aggressively in the Aleppo campaign.

The report relied on interviews with emergency medical workers and other witnesses, photographs that include what appear to show spent gas canisters and analyses of video.

The report acknowledged that "identifying with certainty the chemical used in the attacks without laboratory testing is difficult."

"The pattern of the chlorine attacks shows that they were coordinated with the overall military strategy for retaking Aleppo, not the work of a few rogue elements," Ole Solvang, deputy emergencies director at Human Rights Watch, said in releasing the report.

In all eight instances in which the report concluded chlorine bombs had been used, it said they were dropped in areas where government forces had planned to advance. The report said the attacks, from Nov. 17 to Dec. 13, when the combatants agreed to a cease-fire, killed at least nine civilians, including four children, and hurt 200.